I think he's started to think less of you after this whole BDSM thing. Maybe he's lost respect for u. But he just likes to play and hence he soothes ur mind by appologising. He likes to humilitate u 'cause it gives him a sense of power but at the same time he doesnt understand the complexity of role playing.

It's not worth it according to me. Either keep a vanilla relationship or search for someone who understands.